Breechblock having a timing circuit switch



Nov. 8, 1966 F. E. KNIGHT ETAL 3,283,658

BREECHBLOCK HAVING A TIMING CIRCUIT SWITCH Filed May 24, 1965 INVENTORFRANK E. KNIGHT HOWARD M. wlLDE JOSEPH y. HEANEY BY: m. uw y M 57357{9.9M} MATTORNEY.

UHC

Patented Nov. 8, 1966 3,283,658 BREECHBLOCK HAVING A TIMING CIRCUITSWITCH Frank E. Knight, Philadelphia, Howard M. Wilde, Feasterville, andJoseph W. Heaney, Philadelphia, Pa., assignors to the United States ofAmerica as represented by the Secretary of the Army Filed May 24, 1965,Ser. No. 458,521 3 Claims. (Cl. 89-17) The invention described hereinmay be manufactured and used by -o-r for the Government for governmentalpurposes without the payment to us of :any royalty thereon.

This invention relates to a breechblock for use with ammunition testfiring apparatus.

An object of this invention is -t-o provide a breechblock for use withammunition test firing apparatus including an electrical timingcircuit,` which breechblock comprises means for accurately determiningthe instance a firing pin makes firing contact with the primer of around f test ammunition.

Another object of this invention is to provide a breechblock of theabove type which can be used to fire various ammunitions havingdiffering depths of primer penetration requirements and still provide an.accurate determination of the instant of firing contact with theprimers of a round of test ammunition.

A fur-ther object of this invention is to provide .a breechblock of theabove type wherein the next preceding object is accomplished through asimple external adjustment.

Still .another object of the present invention is to provide abreechblock of the character described wherein a hammer member and acontact pin form conductors in an electrical timing circuit which closeswhen the hammer engages the pin after the hammer ac-ts to move a lfiringpin a prescribed distance equal to the depth of primer penetrationrequired with `a given round of ammunition.

Further objects of the invention will in part be obvious and will inpart .appear hereinafter.

The invention accordingly comprises the apparatus possessing theconstruction, combination of elements and arrangement of parts which areexemplified in the following detailed disclosure, and the scope of theapplica-tion of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,refe-rence should be had to the following detailed descrip-tion taken inconnection with the accompanying drawings wherein:

FIG. 1 is a longitudinal View partly in cross-section of a breechblockembodying the present invention, showing also portions of a typicalammunition test firing apparatus in phantom outline and .showing thebreechblock in a cocked or ready position;

FIG. 2 is a View similar to FIG. l, but showing the inventivebreechblock in its inactive position;

FIG. 3 is a view taken along the line 3 3 of FIG. 2;

FIG. 4 is a portion of FIG. 2 partially sectioned to show therelationship of parts when the breechblock embodying the presentinvention is in its firing position.

Referring .to the drawings, in which like reference characters refer tolike parts throughout the various figures, and referring particularly toFIGS. 1 and 2, 10 represents the breechblock as a whole and illustratesa single embodiment of 4the present invention. The breechblock containsall electrically conductive parts except where -otherwise specified. Thebody 12 of the breechbl-ock 10 is basically cylindri-cal in form and isadapted to be lassembled with parts of ammunition test iiring apparatus.The body 12 has a centrally disposed bore 14 therein. The bore 14extend-s through the body 12 and forms an open rearward end portion ofthe body 12 for insertion of a cooking bar 16, the function of whichwill become apparent further on in this description. The forward endportion of the bore 14 is closed by members which will be describedhereinafter.

A hammer 18 is pivotally mounted in the bore 14 and is held therein bymeans of a pin 20. The pin 20 is mounted in an `appropriate passagewayprovided in the body as shown in FIG. 3, and passes through an openingin the lower end portion of the hammer 18. The lower end of the hammer18 abuts the upper end of a housing 22 which contains a helical coilspring 24 in compression. The spring 24 is fixed with respect to thebody 12 by means of a pin 26 passi-ng through the body 12 and a disc 28or the like fixed to the lower end lof the spring 24. The housing 22contacts the body 12 and is free to slide therein. The spring 24 urgesan upwardly directed force against the housing 22 and thence through thehousing 22 to the hammer 18. The spring 24 and housing 22 together thusprovide power means for driving the hamme-r 18 forwardly from its cockedposition illustrated in FIG. 1.

Fixed to the forward end of the body 12 and forming one part of the bore14 closing is .a plate 30 which carries a spring 32 urged firing pin 34.The firing pin 34 is axially aligned with a nose 35 formed integrallywith the hammer 18. When the hammer 18 is released from its cockedposition the spring 24 will act to urge the hammer 18 in a forwardpivotal movement about the pin 20. The nose 35 will then strike thefiring pin 34 to impart forwardly directed movement thereto. This firingrela- 4tionship is clearly shown in FIG. 4.

Disposed below the plate 30 and forming the remainder of the bo-re 14closing is an insert 36 of electrical insulation material, such .asMicarta for example. The lower end portion of the insert 36 rests in anopening 38 drilled longitudinally in the forward portion of the body 12.A portion of the lower end of the plate 30 abuts the upper end of theinsert 36 to fix it `firmly in the opening 38.

The insert 36 carries a contact pin 40 at substantially right angleswith the axis of the opening 38. The contact pin is threaded on itsouter surface and is in threaded movable relationship with the insert.The forward end of the contact pin 40 is adapted by means of a slot orthe like to be screwed into or out of the insert as desired. Therearward end of the contact pin extends into the bore 14 and touches aportion of the hammer 18 when the hammer 18 is in a firing position asshown in FIG. 4. When the hammer 18 is cocked or in an inactive position(as illustrated in FIGS. l and 2, respectively) the contact pin 40becomes and remains spaced therefrom. The contact pin 40 comprises ahousing 42 carrying at its rearward end a spring 44 urged ball 46. Thispermits the hammer 18 to strike the contact pin 40 with resultingmovement of the ball 46 against the spring 44. This minimizes thetendency of the hammer 18 to move the contact pin 40 out of the insert36.

An insulated bushing 48 is fitted into the remainder of the opening 38.A locking screw 50 is `disposed in the opening 38 and has its upper endcarried by the insert 36y substantial-ly at right angles to the contactpin 40.

When the contact pin 40 is set in its -desired orientation with respectto the hammer 18 the locking screw 50` is turned to urge upon and securethe contact pin 40 against movement.

The body 12 is made part of an electrical circuit 52 which would mostlikely be a timing circuit. The circuit 52 is comprised of electricalwiring 54 suitable to a particular timing circuit application. One endof the wire 54 is connected with the body 12 through a suitableconnector. The body 12 is in intimate contact with the housing 22 whichabuts the hammer 18. Thus, the ham-me-r 18 may be considered as oneconductor of the circuit 52. The wir-ing is connected with a powersource and timer 56 such as a counter chronograph or the like. The otherend of the wiring 54 is firmly attached to the llower end portion of thelocking .screw 50 which urges against the contact pin 40. The contactpin 40 thus forms the other conductor of the circuit.

In operation, the contact pin 40 position relative to the hammer 18 isadjusted in accordance with the depth 'of firing pin 34 penetrationdesired. This depth of penetration is determined by the nature of theprimer of the partioular round of ammunition being test tired. Theurging of the hammer 1S by the spring 24 will cause the firing pin 34 tomove a prescribed distance. The depth of penetration for ring a certainround of ammunition might be less than the total ltiring pin 34movement. Therefore, if a timing circuit were closed after the fullmovement of the ring pin an erroneous time of primer penetration couldpossibly be recorded. By this invention the exact time of tiring contactwith a given primer is recorded since the timer circuit closes exactlyat the time of primer contact.

After the contact pin 40 is set the locking screw 50 is tightened tosecure the contact pin 40. The hammer 18 is cocked by means of thecocking bar 16. The timer circuit 52 is turned `on and the ham-mer 1Sreleased to urge the tiring pin 34 against the primer of the cartridge58. At the exact point of ring contact with the primer the hammer 18engages the contact pin 40 to close the circuit 52 thereby initiatingwhatever timing test is desired.

Since certain changes may be made in the above apparatus withoutydeparting Ifrom the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

We claim: 1. A breechblock for use with ammunition test firing apparatusincluding an electrical timing circuit, comprising la body having a boreformed therein; a slidable tiring pin in the forwa-rd portion of saidbody; a hammer unit movable within said bore and adapted to be move-drearwardly relative to said body to assume a cocked position, saidhammer unit being Ia part of the electrical timing circuit andconstituting a conductor therein;

power means within said bore for propelling said hammer unit in aforwardly direction from said cocked position to strike said ring pinand impart a forwardly directed movement there-to; and

other conducting means carried by said body in the forward portionthereof at a point spaced from said hammer unit in its cocked positionand engageable by a portion of said hammer unit after said unit hasimparted a prescribed -forward movement to said firing pin whereby saidelectrical circuit is closed.

2. A breechblock for use with ammunition test ring apparatus includingan electrical timing circuit, comprislng a body having a bore formedtherein;

a slidable firing pin in the forward portion of said body;

a hammer unit pivotally movable within said bore and adapted to bepivoted rearwardly relative to said body to assume a cocked position,said hammer unit being a part of t-he electrical timing circuit andconstituting a conductor therein;

power means within said bore for propelling said hammer unit in aforwardly direction from said cocked position to strike said tiring pinand impart a forwardly directed movement thereto, and a contact pincarried by said body in the forward position thereof and insulatedtherefrom, said pin forming a second conductor in the electrical timingcircuit, said pin fixed in space relationship with said hammer unit inits cocked position and engageable by a portion of said hammer unitafter said unit has imparted a prescribed forward movement to saidtiring pin whereby said electrical circuit is closed. 3. A breeohblockfor use with ammunition test firing apparatus including lan electricaltiming circuit, comprising a body having a bore forme-d therein; aslidable firing pin in the forward portion of said body; a hammer unitpivotally .movable within said bore and adapted to be pivoted rearwardlyrelative to said body to assume a cocked position, said hammer unitbeing a pa-rt of the electrical timing circuit and constituting aconductor therein;

power means within said bore for propelling said hammer unit in aforwardly direction from said cocked position to strike said ring pinand impart thereto a forwardly directed movement;

a bushing carried by said body in the forward portion thereof, saidbushing being insulated from .said body;

a movable contact pin in said bushing, said pin xed in spacerelationship with said ham-mer unit in its cocked position andengageable by a portion of said hammer unit after said unit has imparteda prescribed forward movement to said tiring pin; and

a movable locking Irod for restraining movement of said contact pin whensaid pin is positioned as desired, said rod and said pin forming asecond conductor in the electrical ltiming circuit, whereby when saidhammer unit contacts said pin the electrical timing circuit is closed.

References Cited by the Examiner UNITED STATES PATENTS 2,473,555 6/1949weiss 89-27 2,517,1-33 8/-1950 Porter 73-167 2,755,439 7/1956 Whitmore73-167 2,868,081 1/1959 Grover 89--135 3,094,932 6/ 1963 Greenlees 42-84SAMUEL FEINBERG, Primary Examiner. S. C. BENTLEY, Assistant Examiner,

1. A BREECHBLOCK FOR USE WITH AMMUNITION TEST FIRING APPARATUS INCLUDINGAN ELECTRICAL TIMING CIRCUIT, COMPRISING A BODY HAVING A BORE FORMEDTHEREIN; A SLIDABLE FIRING PIN IN THE FORWARD PORTION OF SAID BODY; AHAMMER UNIT MOVABLE WITHIN SAID BORE AND ADAPTED TO BE MOVED REARWARDLYRELATIVE TO SAID BODY TO ASSUME A COCKED POSITION, SAID HAMMER UNITBEING A PART OF THE ELECTRICAL TIMING CIRCUIT AND CONSTITUTING ACONDUCTOR THEREIN; POWER MEANS WITHIN SAID BORE FOR PROPELLING SAIDHAMMER UNIT IN A FORWARDLY DIRECTION FROM SAID COCKED POSITION TO STRIKESAID FIRING PIN AND IMPART A FORWARDLY DIRECTED MOVEMENT THERETO; ANDOTHER CONDUCTING MEANS CARRIED BY SAID BODY IN THE FORWARD PORTIONTHEREOF AT A POINT SPACED FROM SAID HAMMER UNIT IN ITS COCKED POSITIONAND ENGAGEABLE BY A PORTION OF SAID HAMMER UNIT AFTER SAID UNIT HASIMPARTED A PRESCRIBED FORWARD MOVEMENT TO SAID FIRING PIN WHEREBY SAIDELECTRICAL CIRCUITS IS CLOSED.